In wireless communication systems, a radio access network generally comprises one or more access nodes (such as a base station) which communicate on radio channels over a radio or air interface with plural wireless terminals. In some technologies such a wireless terminal is also called a User Equipment (UE). A group known as the 3rd Generation Partnership Project (“3GPP”) has undertaken to define globally applicable technical specifications and technical reports for present and future generation wireless communication systems. The 3GPP Long Term Evolution (“LTE”) and 3GPP LTE Advanced (LTE-A) are projects to improve an earlier Universal Mobile Telecommunications System (“UMTS”) mobile phone or device standard in a manner to cope with future requirements.
In LTE telecommunications a mobile station (UE) may be in one of several Radio Resource Control (RRC) states, such as IDLE state or RRC-connected state, for example. In typical cellular mobile communication systems, the reachability by the network of a mobile station (UE) in the IDLE state, i.e. the ability of the network to reach the UE by paging, is achieved by the mobile station occasionally reporting its location. The coverage of the system is divided into several geographic areas, each of which consists of multiple cells. The mobile station reporting takes place when the mobile station moves across the boundary of an area. When the network receives incoming data which should be sent to the mobile station, the network broadcasts a paging message to all of the cells in the area that the mobile station is supposed to be located.
In Long-Term Evolution (LTE) and LTE Advanced (LTE-A), such a geographic area is called a “tracking area” (TA). When first registering with the core network (CN), the user equipment (UE) is given a TA or a list of TAs. Subsequently, when moving out of the coverage of the initially specified TA(s), the UE reports its presence by sending a Tracking Area Update (TAU) message to the core network via a currently camped base station, e.g., an evolved Node B (eNB). As a response, the network then provides the mobile station with an updated TA or a list of TAs.
When a mobile-terminated event (such as an incoming call) occurs, the network attempts to page the UE by broadcasting a Paging message. This Paging message is transmitted from all the eNBs in the TA or TAs in the list where the UE is supposed to be located.
In general, paging is radio resource intensive, since paging uses downlink radio resources on all the cells in the area. A smaller area size might reduce the resource usage, but conversely would increase the number of TAUs that the mobile station needs to perform.
3GPP is currently discussing introduction of an “INACTIVE” state for 5G, where the Radio Access Network (RAN) manages the mobility of the UEs in the state, in order to hide mobility and state transitions from the core network.
What is needed, therefore, and example object(s) of the technology disclosed herein, are methods, apparatus, and techniques to provide area update procedures that are suitable for a 5G system.